1. Field of the Invention
The invention relates to a welding torch including a torch housing and, preferably, a tube bend capable of being fastened thereto, wherein a drive unit for feeding a welding wire is arranged in the torch housing and the drive unit is formed by at least one pair of rollers, in particular a drive roller and a pressure roller, as well as a drive motor.
2. Prior Art
From the prior art, it is known that drive motors used in welding torches are designed as independent assemblies. In those cases, the drive motor has its own stator house, which carries or incorporates all elements like the stator windings or stator magnets, the rotor with the stator pack, in particular rotor windings or rotor magnets, the bearings for the rotor, the end shield and a motor plate. That independent drive motor assembly is fastened to the torch housing. In order to increase the feeding power, a gearbox is fastened to the motor shaft, with a drive roller being attached to the latter to enable wire feeding with an associated pressure roll. This involves the disadvantage of requiring additional or more space, since that stator housing has to be realized in a particularly stable manner for the fixation of the bearing. Another disadvantage resides in that no optimum cooling of the drive motor is feasible, since the forming rotor heat is taken up by the stator housing and no optimum heat removal takes place on account of small cooling surfaces or respective transition resistances to the welding torch.
Another variant embodiment comprises a freely located, aircooled drive motor. Since in that case cooling is effected via the stator housing, it is disadvantageous that only a very small cooling surface is available.
GB 911 649 A, U.S. Pat. No. 4,845,336 A, GB 1 134 664 A, GB 1 080 125 A and GB 1 093 736 A, for instance, describe welding torch constructions including drive motors which are designed as independent assemblies including their own stator housings.